Disciplinary boundaries and integrating care: using Q-methodology to understand trainee views on being a good doctor.

BACKGROUND: Rising numbers of patients with multiple-conditions and complex care needs mean that it is increasingly important for doctors from different specialty areas to work together, alongside other members of the multi-disciplinary team, to provide patient centred care. However, intra-professional boundaries and silos within the medical profession may challenge holistic approaches to patient care. METHODS: We used Q methodology to examine how postgraduate trainees (n = 38) on a range of different specialty programmes in England and Wales could be grouped based on their rankings of 40 statements about 'being a good doctor'. Themes covered in the Q-set include: generalism (breadth) and specialism (depth), interdisciplinarity and multidisciplinary team working, patient-centredness, and managing complex care needs. RESULTS: A by-person factor analysis enabled us to map distinct perspectives within our participant group (P-set). Despite high levels of overall commonality, three groups of trainees emerged, each with a clear perspective on being a good doctor. We describe the first group as 'generalists': team-players with a collegial and patient-centred approach to their role. The second group of 'general specialists' aspired to be specialists but with a generalist and patient-centred approach to care within their specialty area. Both these two groups can be contrasted to those in the third 'specialist' group, who had a more singular focus on how their specialty can help the patient. CONCLUSIONS: Whilst distinct, the priorities and values of trainees in this study share some important aspects. The results of our Q-sort analysis suggest that it may be helpful to understand the relationship between generalism and specialism as less of a dichotomy and more of a continuum that transcends primary and secondary care settings. A nuanced understanding of trainee views on being a good doctor, across different specialties, may help us to bridge gaps and foster interdisciplinary working.

Community characteristics modify the relationship between obesity prevention efforts and dietary intake in children: the Healthy Communities Study.

BACKGROUND: The influence of community characteristics on the effectiveness of childhood obesity prevention efforts is not well understood. OBJECTIVE: Examine the interaction of community characteristics with the relationship between community programmes and policies (CPPs) and dietary intake. METHODS: An observational study of 5138 children in grades K-8 in 130 US communities was conducted in 2013-2015. Key informant interviews identified and characterized CPPs. CPP scores were generated for the number of target behaviours (CPP-Behav) and the number of behaviour change strategies (CPP-Strat) addressed by all CPPs and CPPs with nutrition goals over the prior 6 years in each community. Dietary intake was assessed by dietary screener and included intake of sugar from sugar-sweetened beverages; energy-dense foods; fruits and vegetables; whole grains; and fibre. Multivariate statistical models assessed the interactions between US region, urbanicity, community-level income, and community-level race/ethnicity and CPP scores in relation to dietary intake. RESULTS: CPP-Strat was positively associated with healthier dietary intakes in the Northeast and West, and in high Hispanic communities; the reverse was true in the South, and in high African-American and low-income communities. The CPP-Behav was positively associated with healthier dietary intakes in the South and rural areas, and the reverse was true in the West. CONCLUSION: The relationships between CPP index scores and dietary intake were most strongly influenced by region and urbanicity and to a lesser extent by community-level race/ethnicity and income. Findings suggest that different considerations may be needed for childhood obesity prevention efforts in communities with different characteristics.

Associations of community programs and policies with children's dietary intakes: the Healthy Communities Study.

BACKGROUND: The impact of community-based obesity prevention efforts on child nutrition has not been adequately studied. OBJECTIVE: Examine relationships between number, type and intensity of community programs and policies (CPPs) and child nutrition. METHODS: An observational study of 5138 children (grades K-8) in 130 U.S. communities was conducted in 2013-2015. CPPs were identified by 10-14 key informant interviews per community. CPPs were characterized based on: count, intensity, number of different strategies used and number of different behaviours targeted. Scores for the prior 6 years were calculated separately for CPPs that addressed primarily nutrition, primarily physical activity (PA) or total combined. Child intakes were calculated from a dietary screener and dietary behaviours were based on survey responses. Multi-level statistical models assessed associations between CPP indices and nutrition measures, adjusting for child and community-level covariates. RESULTS: Implementing more types of strategies across all CPPs was related to lower intakes of total added sugar (when CPPs addressed primarily PA), sugar-sweetened beverages (for nutrition and PA CPPs) and energy-dense foods of minimal nutritional value (for total CPPs). Addressing more behaviours was related to higher intakes of fruit and vegetables (for nutrition and total CPPs) and fibre (total CPPs). Higher count and intensity (PA and total CPPs) were related to more consumption of lower fat compared with higher fat milk. A higher count (PA CPPs) was related to fewer energy-dense foods and whole grains. No other relationships were significant at P < 0.05. CONCLUSION: Multiple characteristics of CPPs to prevent obesity appear important to improve children's diets.

Objectives of community policies and programs associated with more healthful dietary intakes among children: findings from the Healthy Communities Study.

BACKGROUND: Rational planning of community policies and programs (CPPs) to prevent obesity requires an understanding of CPP objectives associated with dietary behaviours. OBJECTIVE: The objective of the study is to identify objectives of CPPs associated with healthful dietary behaviours. METHODS: An observational study identified 4026 nutrition CPPs occurring in 130 communities in the prior 6 years. Dietary intakes of fruits and vegetables, added sugar and sugar-sweetened beverages, among others, were reported among 5138 children 4-15 years of age from the communities, using a Dietary Screener Questionnaire with children age 9 years and older (parent assisted) or parent proxies for younger children. CPPs were documented through key informant interviews and characterized by their intensity, count, and objectives including target dietary behaviour and food environment change strategy. Associations between dietary intakes and CPP objectives were assessed using hierarchical statistical models. RESULTS: CPPs with the highest intensity scores that targeted fast food or fat intake or provided smaller portions were associated with greater fruit and vegetable intake (0.21, 0.19, 0.23 cup equivalents/day respectively with p values <0.01, 0.04, 0.03). CPPs with the highest intensity scores that restricted the availability of less healthful foods were associated with lower child intakes of total added sugar (-1.08 tsp/day, p < 0.01) and sugar from sugar-sweetened beverages (-1.63 tsp/day, p = 0.04). Similar associations were observed between CPP count and dietary outcomes. No other significant associations were found between CPP target behaviours or environmental strategies and dietary intakes/behaviours. CONCLUSION: CPPs that targeted decreases in intakes of less healthful foods and/or aimed to modify the availability of less healthful foods and portions were associated with healthier child dietary behaviours.

'It's surprising how differently they treat you': a qualitative analysis of trainee reflections on a new programme for generalist doctors.

OBJECTIVES: An increase in patients with long-term conditions and complex care needs presents new challenges to healthcare providers around the developed world. In response, more broad-based training programmes have developed to better prepare trainees for the changing landscape of healthcare delivery. This paper focuses on qualitative elements of a longitudinal, mixed-methods evaluation of the postgraduate, post-Foundation Broad-Based Training (BBT) programme in England. It aims to provide a qualitative analysis of trainees' evaluations of whether the programme meets its intentions to develop practitioners adept at managing complex cases, patient focused care, specialty integration and conviction in career choice. We also identify unintended consequences. SETTING: 9 focus groups of BBT trainees were held over a 12-month period. Discussions were audio-recorded and subjected to directed content analysis. Data were collected from trainees across all 7 participating regions: East Midlands; West Midlands; Severn; Northern; North Western; Yorkshire and Humber; Kent, Surry and Sussex. PARTICIPANTS: Focus group participants (61 in total) from the first and second cohorts of BBT. RESULTS: Evidence from trainees indicated that the programme was meeting its aims: trainees valued the extra time to decide on their onward career specialty, having a wider experience and developing a more integrated perspective. They thought of themselves as different and perceived that others they worked alongside also saw them as different. Being different meant benefitting from novel training experiences and opportunities for self-development. However, unintended consequences were feelings of isolation, and uncertainty about professional identity. CONCLUSIONS: By spanning boundaries between specialties, trainee generalists have the potential to improve experiences and outcomes for patients with complex health needs. However, the sense of isolation will inhibit this potential. We employ the concept of 'belongingness' to identify challenges related to the implementation of generalist training programmes within existing structures of healthcare provision.

Omega-3 supplementation during the first 5 years of life and later academic performance: a randomised controlled trial.

BACKGROUND/OBJECTIVES: Consumption of oily fish more than once per week has been shown to improve cognitive outcomes in children. However, it is unknown whether similar benefits can be achieved by long-term omega-3 fatty acid supplementation. The objective was to investigate the effect of omega-3 fatty acid supplementation during the first 5 years of life on subsequent academic performance in children by conducting a secondary analysis of the CAPS (Childhood Asthma Prevention Study). SUBJECTS/METHODS: A total of 616 infants with a family history of asthma were randomised to receive tuna fish oil (high in long-chain omega-3 fatty acids, active) or Sunola oil (low in omega-3 fatty acids, control) from the time breastfeeding ceased or at the age of 6 months until the age of 5 years. Academic performance was measured by a nationally standardised assessment of literacy and numeracy (National Assessment Program Literacy and Numeracy (NAPLAN)) in school years 3, 5, 7 and 9. Plasma omega-3 fatty acid levels were measured at regular intervals until 8 years of age. Between-group differences in test scores, adjusted for maternal age, birth weight and maternal education, were estimated using mixed-model regression. RESULTS: Among 239 children, there were no significant differences in NAPLAN scores between active and control groups. However, at 8 years, the proportion of omega-3 fatty acid in plasma was positively associated with the NAPLAN score (0.13 s.d. unit increase in score per 1% absolute increase in plasma omega-3 fatty acid (95% CI 0.03, 0.23)). CONCLUSIONS: Our findings do not support the practice of supplementing omega-3 fatty acids in the diet of young children to improve academic outcomes. Further exploration is needed to understand the association between plasma omega-3 fatty acid levels at 8 years and academic performance.

The effect of dairy consumption on blood pressure in mid-childhood: CAPS cohort study.

BACKGROUND/OBJECTIVES: It has been postulated that a higher dairy consumption may affect blood pressure regulation. The aim of this study was to examine the association between dairy consumption and blood pressure in mid-childhood. SUBJECTS/METHODS: Subjects (n = 335) were participants of a birth cohort at high risk of asthma with information on diet at 18 months and blood pressure at 8 years. Multivariate analyses were used to assess the association of dairy consumption (serves) and micronutrient intakes (mg). In a subgroup of children (n = 201), dietary intake was also measured at approximately 9 years. RESULTS: Children in the highest quintile of dairy consumption at 18 months had lower systolic blood pressure (SBP) and diastolic blood pressure (DBP) at 8 years (2.5 mm Hg, P=0.046 and 1.9 mm Hg, P = 0.047, respectively) than those in the lowest quintiles. SBP was lowest among children in the highest quintiles of calcium, magnesium and potassium intakes. Significant negative linear trends were observed between SBP and intakes of dairy serves, calcium, magnesium and potassium. Furthermore, SBP and DBP were lowest in the group of children that consumed at least two dairy serves at both 18 months and the follow-up dietary data collection at 9 years, compared with all other children (SBP 98.7 vs 101.0 mm Hg, P = 0.07; and DBP 56.5 vs 59.3 mm Hg, P = 0.006, respectively). CONCLUSION: These results are consistent with a protective effect of dairy consumption in childhood on blood pressure at age 8 years.

Infant and early childhood dietary predictors of overweight at age 8 years in the CAPS population.

BACKGROUND/OBJECTIVES: Programs to address obesity are a high priority for public policy especially for young children. Research into dietary determinants of obesity is challenging but important for rational planning of interventions to prevent obesity, given that both diet and energy expenditure influence weight status. We investigated whether early life dietary factors were predictive of weight status at 8 years in a cohort of Australian children. SUBJECTS/METHODS: We used data from the Childhood Asthma Prevention Study-a birth cohort at high risk of asthma. Dietary data (3-day weighed food records) were collected at 18 months and height, weight and waist circumference were collected at 8 years. We assessed the relationship between dietary predictor variables and measures of adiposity using linear regression. RESULTS: Intakes of protein, meat and fruit at age 18 months were positively associated with measures of adiposity at age 8 years, namely, body mass index and/or waist circumference. We also showed a significant negative relationship between these measures of adiposity at 8 years and intake at 18 months of dairy foods as a percent of total energy, and intake of energy dense cereal-based foods such as cookies and crackers. CONCLUSIONS: This birth cohort study with rigorous design, measures and analyses, has shown a number of associations between early dietary intake and subsequent adiposity that contribute to the growing evidence base in this important field.

Food and nutrient consumption trends in older Australians: a 10-year cohort study.

BACKGROUND/OBJECTIVES: Few longitudinal population-based cohort studies of older people have described dietary intakes over time. The objective of this study was to assess changes in the food and nutrient intake in a cohort of older Australians, using longitudinal data collected over 10 years. SUBJECTS/METHODS: Population-based cohort of people aged 49 years and over at baseline (82% of those eligible) living in two postcode areas, west of Sydney. In 1992-1994, 3654 people were examined; 2334 were reexamined after 5 years and 1952 after 10 years (75% survivors at both examinations). A 145-item food frequency questionnaire was used to assess food and nutrient intake on each occasion, and 1166 participants provided usable dietary data at all three examinations. RESULTS: Energy and sugar intake significantly increased among women over the 10-year period (P-value for trend <0.0001). Long-chain omega-3 fatty acid and fish intake significantly increased in both men and women (P-value for trend <0.0001). Folate intake significantly increased in both men and women (women: 325 dietary folate equivalents (DFE) vs 403 DFE; men: 346 DFE vs 425 DFE, P<0.0001). Wholemeal/grain bread consumption decreased in both men and women (P-value for trend <0.0001). CONCLUSIONS: Many of the observed changes in diet over the 10-year period were consistent with current population dietary recommendations. Some changes, however, appear to have been due to poorer dietary choices. This information could be used to inform nutrition policy and programs targeted to older persons. These data highlight the need to identify barriers to better food choices.

Consumption of 'extra' foods by Australian adults: types, quantities and contribution to energy and nutrient intakes.

OBJECTIVES: To identify the types and quantities of 'extra' foods, or energy-dense, nutrient-poor foods, consumed by Australian adults, and assess their contribution to total energy and nutrient intakes. SUBJECT/METHODS: We used 24-h recall data from 10 851 adults, aged 19 years and over, who participated in the nationally representative 1995 National Nutrition Survey. 'Extra' foods were defined using principles outlined in the Australian Guide to Healthy Eating and by applying cut points for maximum amounts of fat and sugar within each food category. RESULTS: 'Extra' foods contributed to 36% of daily energy intake with the highest contributors being fried potatoes (2.8%), margarine (2.6%), cakes and muffins (2.5%), beer (2.4%), sugar-sweetened soft drinks (2.4%), and meat pies (2.2%). Both age and sex were important determinants of 'extra' foods intake; younger adults were more likely to consume sugar-sweetened soft drinks, fried potatoes, meat pies and savoury pastries, pizza, crisps, lollies and chocolate; whereas older adults were more likely to consume sweet and savoury biscuits, cakes and muffins, margarine and butter. In all age groups, 'extra' foods contributed more to energy intake for men than women. Overall, 'extra' foods contributed 16% protein, 41% total fat, 41% saturated fat, 47% sugar and approximately 20% of selected micronutrients to the diet. CONCLUSIONS: 'Extra' foods contribute excessively to the energy, fat and sugar intakes of Australian adults, while providing relatively few micronutrients. This is of concern for the increasing risk of overweight and chronic disease and poor micronutrient status.

Consumption of 'extra' foods by Australian children: types, quantities and contribution to energy and nutrient intakes.

OBJECTIVE: To measure the types and quantities of energy-dense, nutrient-poor 'extra' foods consumed by Australian children and adolescents and their contribution to total energy and nutrient intakes. DESIGN, SETTING AND SUBJECTS: We used data from 3007 children, aged 2-18 years, who participated in the nationally representative 1995 National Nutrition Survey. Intake was determined by 24-h recall and 'extra' foods were defined using principles outlined in the Australian Guide to Healthy Eating (AGHE) and by applying cut points for maximum amounts of fat and sugar within each food category. RESULTS: All children (99.8%) consumed at least one 'extra' food and the most commonly consumed were margarine, sugar-sweetened soft drinks, cordials and sugar. 'Extra' foods contributed 41% of daily energy intake. Those foods contributing most to energy intake were fried potatoes (4.2%), sugar-sweetened soft drinks (3.3%), ice cream/ice confection (3.1%) and cordials (2.7%). Age and sex were important determinants of 'extra' food intake, with males and older children generally consuming more and different types of, 'extra' foods than females and younger children. 'Extra' foods contributed 19% protein, 47% total fat, 47% saturated fat, 54% sugar, and approximately 20-25% of selected micronutrients to the diet. Calcium and zinc intakes from core foods were below 70% of the recommended dietary intakes for adolescent girls. CONCLUSIONS: 'Extra' foods are over-consumed at two to four times the recommended limits and contribute excessively to the energy, fat and sugar intakes of Australian children, while providing relatively few micronutrients. This is of concern in terms of children's weight and nutrient status.

Folate fortification: potential impact on folate intake in an older population.

OBJECTIVE: To examine the potential impact of different models of folate fortification of Australian foods on the folate intakes of older Australians. DESIGN: Dietary data were collected using a food frequency questionnaire from people attending a population-based health study. SETTING: Two postcode areas west of Sydney, Australia. SUBJECTS: A total of 2895 people aged over 49 y, obtained from a door knock census (79% of 3654 subjects examined). MAIN OUTCOME MEASURES: The folate intake in this population was estimated using four different models: (1) pre-fortification folate values; (2) current voluntary folate fortification in Australia; (3) universal fortification of all foods permitted to add folate, at 25% recommended dietary intake (RDI) per reference serve; and (4) universal fortification of all foods permitted to add folate, at 50% RDI per reference serve. The increased bioavailability of synthetic folic acid (SFA) was included in the analysis. RESULTS: At current voluntary folate fortification, approximately 65% of this population consume 320 microg dietary folate equivalents (DFE) or more per day from diet and supplements, and 0.4% (n=10) consume greater than the recommended upper safety level of 1000 microg from SFA. More than 95% of this older population would be expected to consume more than 320 microg DFE from diet and supplements with universal fortification at 50% of the RDI, and 0.5% (n=14) may consume greater than 1000 microg/day of SFA. CONCLUSIONS: There is unlikely to be a large increase in the proportion of older persons who are likely to consume more than the upper safety level of intake with universal folate fortification. As most of those who currently or are predicted to consume over 1000 microg SFA take supplements containing folic acid, it is highly recommended that vitamin B12 be included in any vitamin supplements containing folate. SPONSORSHIP: This study was supported by the Australian National Health and Medical Research Council (NHMRC).

Prevalence and socio-demographic predictors of dietary goal attainment in an older population.

OBJECTIVE: To describe the measured dietary intakes and anthropometry of a large, free-living population of middle-aged and older Australians who participated in the Australian Blue Mountains Eye Study (BMES), and to identify the socio-demographic characteristics associated with attainment or non-attainment of dietary goals. METHOD: Anthropometry and dietary intakes were compared with current population dietary goals and Recommended Dietary Intakes for 2,873 people (79% of eligible residents) aged > or = 49 years who participated in the BMES. Nutrient intakes were measured by a validated food frequency questionnaire. RESULTS: Nutrients for which mean intakes deviated most from nutrition goals included: percentages of energy from total and saturated fat, carbohydrate and alcohol (men), as well as absolute intakes of calcium, zinc and fibre. More than half the men (60%) and women (54%) were overweight or obese. Several micro-nutrient goals were more likely to be met in households where the respondents and/or their spouses were independent. Married men were more likely to meet goals for fibre and iron, but less likely to meet the goal for cholesterol. Several goals were more likely to be met by men and women who had qualifications after leaving school, those with higher job status and non-pensioners, suggesting an socio-economic status dimension. CONCLUSIONS AND IMPLICATIONS: These results indicate that over- rather than under-nutrition is more prevalent among community-dwelling older people, although under-nutrition should not be overlooked. Particular sub-groups that are less likely to meet some dietary goals may require targeting in community nutrition interventions.

A comparison of amitriptyline, vasopressin and amitriptyline with vasopressin in nocturnal enuresis.

Forty-five children aged 6-14 years with primary nocturnal enuresis were randomised to determine whether desmopressin is more effective than amitriptyline and whether the combination of amitriptyline/desmopressin is more effective than amitriptyline or desmopressin alone. Amitriptyline dosage was 25 mg for children 6-10 years and 50 mg for children aged 10-14 years. Desmopressin (20 micrograms) was given in the same dosage for all age groups. After a run-in period of 2 weeks, children were treated for 16 weeks and then observed for 12 weeks. In the amitriptyline group mean wet nights per week decreased from 5.8 +/- 0.9 to 3.3 +/- 1.9 (P < 0.0005); in the desmopressin group mean wet nights per week decreased from 6.0 +/- 0.9 to 4.7 +/- 1.7 (P < 0.02); in the amitriptyline/desmopressin group mean wet nights per week decreased from 6.3 +/- 0.9 to 3.3 +/- 2.5 (P < 0.0006). When comparing the groups, amitriptyline/desmopressin and amitriptyline were statistically more effective than desmopressin in week 6 (P < 0.009), week 8 (P < 0.03) and week 10 (P < 0.04). No significant side effects occurred. At this dose amitriptyline was more effective than desmopressin and the combination of desmopressin and amitriptyline did not confer any additional benefit.

The implications of underreporting in dietary studies.

Dietary data from the Western Sydney Dietary Survey 1989-90 (n = 512) was used to investigate: 1. the prevalence and predictors of underreporting of energy intake, 2. the effects on results of excluding data from underreporters for analysis of mean nutrient intakes, and 3. the proportion of energy intake supplied by macronutrients and proportions of subjects who met dietary goals. The proportion whose measured energy intakes from a Food Frequency Questionnaire (FFQ) were below cutpoints for biologic plausibility was 28.5 per cent; it was higher for subjects who had BMI > 25 and were female. Point estimates for mean intakes of energy and nutrients were all greater when data from underreporters were excluded, but nutrient intakes expressed as percentages of energy intake remained largely unchanged. Increases in estimated mean population intake for each nutrient ranged from 7 per cent to 14 per cent for males, and 12 per cent to 17 per cent for females. Estimates of the percentages of the sample who did not meet dietary goals were significantly lower for a number of nutrients when underreporters were excluded. We conclude that: 1. results expressed as a percentage of energy intake are not affected by the exclusion of energy underreporters, and 2. estimates of the proportion of populations meeting some nutrient goals and associations between diet and disease are likely to change meaningfully and significantly with the exclusion of data from underreporters.

Cyclosporin therapy in steroid-dependent nephrotic syndrome.

Five children with multiple relapsing steroid-dependent nephrotic syndrome were treated with continuous cyclosporin for periods ranging from 18 to 48 months. Renal biopsy showed mild mesangial proliferation in three of the children and minimal change in two. All children previously had been treated with cyclophosphamide. Cyclosporin was started during remission at 5 mg/kg per day. If a relapse occurred the dose was increased until a trough blood level of 100-250 ng/mL (HPLC) was achieved. In the initial 12 months of treatment, the mean number of relapses decreased from 6.4 +/- 0.54 (s.d.) per annum to 1.6 +/- 1.3 per annum (P < 0.01). Cyclosporin was effective in maintaining long-term remission in four of the five patients. Side effects included hypertrichosis (5) and gum hyperplasia (1). The mean creatinine clearance decreased from 126 +/- 16 to 97 +/- 22 mL/min per 1.73 m2 (P = NS). A renal biopsy in all five patients after 12 months therapy showed no nephrotoxicity. A further biopsy in one patient after 4 years therapy showed interstitial fibrosis. Cyclosporin should be considered in children with steroid-dependent nephrotic syndrome who show signs of steroid toxicity and have only a short remission period after cyclophosphamide. Serial renal biopsies are recommended if prolonged therapy is used.

Evaluation of automated threshold selection methods for accurately sizing microscopic fluorescent cells by image analysis.

The accurate measurement of bacterial and protistan cell biomass is necessary for understanding their population and trophic dynamics in nature. Direct measurement of fluorescently stained cells is often the method of choice. The tedium of making such measurements visually on the large numbers of cells required has prompted the use of automatic image analysis for this purpose. Accurate measurements by image analysis require an accurate, reliable method of segmenting the image, that is, distinguishing the brightly fluorescing cells from a dark background. This is commonly done by visually choosing a threshold intensity value which most closely coincides with the outline of the cells as perceived by the operator. Ideally, an automated method based on the cell image characteristics should be used. Since the optical nature of edges in images of light-emitting, microscopic fluorescent objects is different from that of images generated by transmitted or reflected light, it seemed that automatic segmentation of such images may require special considerations. We tested nine automated threshold selection methods using standard fluorescent microspheres ranging in size and fluorescence intensity and fluorochrome-stained samples of cells from cultures of cyanobacteria, flagellates, and ciliates. The methods included several variations based on the maximum intensity gradient of the sphere profile (first derivative), the minimum in the second derivative of the sphere profile, the minimum of the image histogram, and the midpoint intensity. Our results indicated that thresholds determined visually and by first-derivative methods tended to overestimate the threshold, causing an underestimation of microsphere size. The method based on the minimum of the second derivative of the profile yielded the most accurate area estimates for spheres of different sizes and brightnesses and for four of the five cell types tested. A simple model of the optical properties of fluorescing objects and the video acquisition system is described which explains how the second derivative best approximates the position of the edge.

Algorithm to estimate cell biovolume using image analyzed microscopy.

This paper describes an algorithm for calculating the biovolume of cells with simple shapes, such as bacteria, flagellates, and simple ciliates, from a 2-dimensional digital image. The method can be adapted to any image analysis system which allows access to the binary cell image--(i.e., the pixels, or (x,y) points, composing the cell. The cell image is rotated to a standard orientation (horizontal), and a solid of revolution is calculated by digital integration. Verification and a critical assessment of the method are presented. The algorithm accounts for irregularities in cell shape that conventional methods based on length, width, and geometrical formulas do not.

Dietary compliance among insulin-dependent diabetics.

An education program to improve dietary compliance in insulin-dependent diabetics was evaluated from 1978 to 1980 at the Royal North Shore Hospital of Sydney. Dietary intake, biochemical status, health beliefs, knowledge, anthropometric and other measurements were made on 140 diabetics and their family members before and, where possible, 6 months after the program. Four aspects of compliance were assessed: dietary composition, body weight, carbohydrate spacing among meal periods and carbohydrate variation between days. There was a significant increase in the proportion of subjects who achieved the recommended goal of a high carbohydrate/low fat diet. Diabetics who complied with this recommendation were significantly more likely to have adequate glycemic control. Most of the participants were initially near ideal weight and there were few substantial weight changes. The proportions of diabetics with acceptable scores for carbohydrate spacing and variation did not change significantly. Subjects who complied with one aspect of the dietary regimen did not necessarily comply with other aspects. Dietary compliance was related to initial patterns of dietary intake but could not be predicted from any other factors such as demographic characteristics, duration of disease, knowledge or health beliefs, although this could have been due to small sample sizes.